As will be understood by those skilled in the art of painting vehicle bodies, for example, it is critical to properly cure the paint following application. The paint on large articles, such as vehicle bodies, is cured in a paint oven which typically includes several zones or stages, including multiple preheat zones, hold or bake zones and multiple cooler zones. Each of the zones typically includes upper and lower air nozzles which blow heated or cooling air on the painted bodies. The vehicle body is conveyed through the oven on a central conveyor. If the paint is not fully cured, this may compromise the paint quality, cause the paint to fall off the article and result in color issues. If the paint is over cured, the paint may become brittle or discolored. In a typical automotive application, the paint supplier provides a “cure window,” which includes time and temperature. For example, an e-coat cure window may be fifteen minutes at 330° F. or higher with a maximum of 400° F. A typical paint oven may have a length of 200 to 1,000 feet and include two or more preheat zones, three or more hold zones and three or more cooling zones. As used herein, the term “paint” includes any coating, adhesive, glue or sealant which requires curing by heating. When curing paint on large objects, such as vehicle bodies, it is important to take into account the thickness of the substrate. As understood by those skilled in this art, relatively thin metal panels, such as the vehicle roof, side panels and fenders heat quickly, whereas heavier areas, such as the pillars and portions of the undercarriage heat far more slowly. Further, each vehicle body design will have different areas of concern or interest and thus it would be desirable to design a bake oven tailored to the design of the vehicle body or other article for curing paint on the article to achieve the desired cure criteria for predetermined areas of the article. The method of designing a bake oven of this invention achieves this object.
At present, a vehicle paint bake oven is designed primarily by trial and error. That is, a vehicle body is conveyed through a mock up of a paint oven and temperature sensors or probes measure the temperature of several areas of the vehicle body. Simulations of vehicle bodies and paint ovens have also been tried without success. The method of this invention simplifies the simulation and achieves the desired paint cure.